Recently it has become more and more attractive to produce electrically conductive patterns onto dielectric substrates such as paper, cardboard, fabric, or polymer films, by using printing processes. The technical field of printed electronics involves producing electrically conductive—and in some cases semiconductive—areas and tracks on the substrate, frequently augmented by attaching separate electronic components such as semiconductor chips to at least some of the conductive or semiconductive areas.
As such, printing on paper or the like has been known since the times of the Gutenberg press in the fifteenth century. However, simply replacing traditional, non-conductive printing inks or toners with electrically conductive ones is far from straightforward. Inherent characteristics of the prior art techniques may make it difficult or impossible to change to conductive inks or toners. Many planned applications of printed electronics involve disposable products such as packages for daily consumables, which sets considerable pressure on economical factors: the packaging or its printing should not cost very much. It is possible to take a conductive or semiconductive polymer in the form of a liquid solution and use it as an ink in a printing press or an inkjet printer, but most conductive polymers known at the time of writing this description are too expensive or difficult to handle for large-scale exploitation as inks. Many metallic compounds are relatively inexpensive as such and can be used in the form of small, solid granules to make a paste, but pulverizing them down to the particle size required to e.g. smoothly flow through inkjet nozzles or conveniently fit to gravure printing radically increases their price.